Droplet generating device and droplet generating method

ABSTRACT

A droplet generating device includes a tube defining a area in which air including particles flows along a first direction and an evaporation and condensation unit disposed in the tube to intersect with the first direction, the evaporation and condensation unit supplying vapor in the area to supersaturate the area to condense the vapor on surfaces of the particles to form a droplet. Accordingly, droplets may be effectively generated.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Phase entry of PCT Application No.PCT/KR2017/000087 filed Jan. 4, 2017, which application claims thebenefit of priority to KR Application No. 10-2016-0003046, filed Jan.11, 2016, the entire disclosures of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

Example embodiments of the present invention relate to a dropletgenerating device and a droplet generating method. More particularly,example embodiments of the present invention relate to a dropletgenerating device and a droplet generating method for supplying aircontaining particles and condensing vapor on surfaces of the particlesto generate a droplet.

2. Description of the Related Art

As a modern industry has developed, particles have been generated fromfactories or automobiles as air pollutants. As a problem of airpollution becomes serious, there have been active researches on thetechnology for removing pollutants from the air.

A filter has been generally used to remove the contaminant particlesfrom the air. However, in the case of a filter, the removal efficiencyvaries depending on the sizes of the particles, which might cause thefilter to be limitedly used. Furthermore, there is a problem that theefficiency of the filter deteriorates as the filter has been used for along time.

Accordingly, there is a need for a droplet generating device and adroplet generating method capable of generating droplets by supplyingvapor to the surfaces of particles having a relatively small size andcondensing the vapor on the surfaces of the particles.

U.S. Pat. No. 8,449,657, of which the present inventor filed to theUnited States Patent and Trademark Office, discloses that air containingparticles flows along a direction of extension of a tube, and vapor isprovided into the tube using diffusion phenomena and a pressuredifference.

In this case, a relative humidity in the tube along a second directionperpendicular to the extension direction may have a non-uniform degreeof supersaturation gradient. Therefore, a problem that sizes of thedroplets agglomerated along the second direction are not uniform mayoccur.

In addition, there is a difficulty in uniformly condensing the vapor inthe particles contained in the air, as the air in the tube has anon-uniform temperature gradient along the second directionperpendicular to the extending direction.

SUMMARY OF THE INVENTION

Example embodiments of the present invention provide a dropletgenerating device capable of efficiently generating droplets bysupplying vapor to air containing particles to condense the vapor on thesurfaces of the particles.

Example embodiments of the present invention provide a dropletgenerating method capable of efficiently generating droplets bysupplying vapor to air containing particles to condense the vapor on thesurfaces of the particles.

According to one aspect of the present invention, there is provided adroplet generating device including a tube defining a area in which airincluding particles flows along a first direction and an evaporation andcondensation unit disposed in the tube to intersect with the firstdirection, the evaporation and condensation unit supplying vapor in thearea to supersaturate the area to condense the vapor on surfaces of theparticles to form a droplet.

In an example embodiment of the present invention, the evaporation andcondensation unit may be arranged to be inclined at 5 to 90 degrees withrespect to the first direction.

In an example embodiment of the present invention, the evaporation andcondensation unit may be arranged entirely over a vertical section ofthe area perpendicular to the first direction.

In an example embodiment of the present invention, the evaporation andcondensation unit may have at least one mesh structure including aplurality of wires randomly arranged such that the mesh structure mayinclude a through hole formed between the wires.

Here, each of the wires includes may include a liquid-absorbing layerincluding a hydrophilic material capable of holding the liquid as asource of the vapor, and a heating element for heating liquid formed onsurfaces thereof.

In an example embodiment of the present invention, each of the wires mayinclude a concave-convex pattern or a hydrophilic surface coating layerfor holding liquid using a capillary force.

In the meantime, the heating element may evaporate the vapor from thesurface of the wires

In an example embodiment of the present invention, a plurality of meshstructures is spaced apart from each other.

In an example embodiment of the present invention, a supersaturationdegree is uniformly formed as a whole along a second directionperpendicular to the first direction at a specific point along the firstdirection.

In an example embodiment of the present invention, a temperaturedistribution is uniformly formed as a whole along a second directionperpendicular to the first direction at a specific point along the firstdirection.

According to one aspect of the present invention, there is provided adroplet generating device. The droplet generating method includesproviding air including particles in a tube defining a area along afirst direction and providing vapor in the area and maintaining auniform supersaturation degree as a whole along a second directionperpendicular to the first direction to condense the vapor on surface ofthe particles.

In an example embodiment of the present invention, maintaining theuniform supersaturation degree is performed using a evaporation andcondensation unit arranged in the tube to intersect with the firstdirection.

In an example embodiment of the present invention, maintaining theuniform supersaturation degree includes forming a temperaturedistribution uniformly as a whole along a second direction perpendicularto the first direction at a specific point along the first direction.

According to example embodiments of the present invention, the dropletgenerating device includes the evaporation and condensation unitarranged to intersect with the direction of air flow in a tube, capableof condensing the vapor on the surface of the particle by supplying thevapor in the area and forming the area in the supersaturated state.Therefore, the supersaturated state in the area can be maintaineduniformly. As a result, the vapor can be effectively condensed on thesurfaces of the particles contained in the air flowing in the area toform droplets effectively.

Further, the air containing the particles can reach to the evaporationand condensation unit uniformly such vapor can effectively make contactwith the particles to effectively condense the vapor on the surfaces ofthe particles.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present inventionwill become more apparent by describing in detailed example embodimentsthereof with reference to the accompanying drawings, in which:

FIG. 1 is a cross-sectional view illustrating a droplet generatingdevice in accordance with an example embodiment of the presentinvention;

FIG. 2 is a side view of the droplet generating device in FIG. 1;

FIG. 3 is a graph showing a supersaturation degree along a seconddirection (Y-direction);

FIG. 5 is a cross-sectional view illustrating a wire included in aevaporation and condensation unit;

FIG. 6 is a graph illustrating sizes of particles and droplets along afirst direction (X-direction); and

FIG. 7 is a flow chart illustrating a droplet generating method inaccordance with an example embodiment of the present invention.

DESCRIPTION OF THE EMBODIMENTS

Hereinafter, a droplet generating device and a droplet generating methodin accordance with example embodiments of the present invention aredescribed more fully hereinafter with reference to the accompanyingdrawings, in which embodiments of the invention are shown. Thisinvention may, however, be embodied in many different forms and shouldnot be construed as limited to the embodiments set forth herein. Rather,these embodiments are provided so that this disclosure will be thoroughand complete, and will fully convey the scope of the invention to thoseskilled in the art. In the drawings, the sizes and relative sizes oflayers and areas may be exaggerated for clarity.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, components, areas, layersand/or sections, these elements, components, areas, layers and/orsections should not be limited by these terms. These terms are only usedto distinguish one element, component, area, layer or section fromanother area, layer or section. Thus, a first element discussed belowcould be termed a second element without departing from the teachings ofthe present invention.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

FIG. 1 is a cross-sectional view illustrating a droplet generatingdevice in accordance with an example embodiment of the presentinvention. FIG. 2 is a side view of the droplet generating device inFIG. 1. FIG. 3 is a graph showing a supersaturation degree along asecond direction (Y-direction).

Referring to FIGS. 1 to 3, a droplet generating device 100 in accordancewith an example embodiment includes a tube 110 and an evaporation andcondensation unit 120. The droplet generating device 100 may generate adroplet on surfaces of particles contained in air using condensationphenomena.

The air contains the particles. That is, the particles include finedusts or ultrafine dusts each having a nano size. Alternatively, theparticles include living organism containing viruses. The particles maybe organic particles or inorganic particles.

The air has a first temperature, which is relatively low.

The tube 110 defines an area in which the air containing the particlesflows along a first direction. That is, a direction along which the airflows is defined as the first direction (or an X-direction). Further, adirection perpendicular to the first direction is defined as a seconddirection (or a Y-direction).

The tube 110 may have a cylindrical shape having a hollow therein.Alternatively, the tube 110 may have a polygonal column shape having ahollow therein. That is, it is sufficient that the tube 110 has a hollowformed therein to provide the area, and a shape of the tube 110 is notlimited thereto.

The tube 110 has an inlet through which the air flows into the hollowand an outlet through which the air flows outwardly from the hollow.That is, the tube 110 includes both the inlet and the outlet throughwhich the air flows along the first direction.

The evaporation and condensation unit 120 is disposed in the tube 110.Further, the evaporation and condensation unit 120 is arranged tointersect with respect to the first direction. Therefore, the air whichis flowing in the tube 110 in the first direction makes direct contactwith the evaporation and condensation unit 120, such that the vaporprovided from the evaporation and condensation unit 120 may beeffectively condensed on surfaces of the particles.

In addition, the evaporation and condensation unit 120 can allow the airto meet the evaporation and condensation unit 120 to locally change aflow direction of the air. That is, the air flows as a whole along thefirst direction and flows locally in a direction differently from thefirst direction. As a result, the air flow is locally shaken within thearea, and the air swirling time can be prolonged. In addition,turbulence such as vortices can occur. As a result, as the turbulence islocally formed, the swirling time of the particles contained in the airadjacent to the evaporation and condensation unit 120 can be increased.As a result, droplets containing the particles and the condensed liquidcan be generated more effectively.

The evaporation and condensation unit 120 supplies vapor within the areato make the area through a saturated state into a supersaturated state.In other words, the evaporation and condensation unit 120 vaporizesliquid that is being held and supplies the vapor in the area. Therefore,a supersaturated state can be formed in the area adjacent to theevaporation and condensation unit 120 disposed in the area.

That is, before the evaporation and condensation unit 120 is driven, theevaporation and condensation unit 120 holds the liquid but does notgenerate steam. On the other hand, when the evaporation and condensationunit 120 is driven, the evaporation and condensation unit 120 holdingthe liquid generates vapor to supply the vapor within the area. Thus,the vapor is supplied into the area such that the area is converted intothe supersaturated state.

Further, the air which is flowing in the area adjacent to theevaporation and condensation unit 120 meets the vapor in asupersaturated state, and the vapor condenses on the surfaces of theparticles. Therefore, a droplet having vapor condensed on the surfacesof the particles is generated.

According to an embodiment of the present invention, the evaporation andcondensation unit 120 is arranged in the tube 110 instead of theevaporation and condensation unit being arranged along an inner wall ofthe tube, the air makes effectively contact with the evaporation andcondensing unit 120 along a flowing direction of the air. Thus, thevapor provided from the evaporation and condensation unit 120 can beefficiently condensed on the surfaces of the particles included in theair, such that the droplet generation efficiency can be improved.

In the example of an example embodiment of this invention, theevaporation and condensation unit 120 can be inclined with a slope angleof 5 to 90 degrees with respect to the first direction.

If the evaporation and condensate unit 120 is arranged parallel to acentral axis extending in the first direction within the tube 110(comparative Example 1), a degree of supersaturation in the area may bedifferent depending on a distance from the evaporation and condensationunit 110. For example, a relative humidity becomes about 100% at aposition where steam is supplied from the evaporation condensing unit,and a relative humidity increases as a position of the evaporating andcondensing unit is distant away from the evaporation and condensingunit. Further, a relative humidity reversely decreases as the positionapproaches to the side innerwall away from the central axis of the tube.Thus, the tube has different degrees of supersaturation, depending onthe position of the tube in the second direction.

When the evaporation and condensation unit is arranged parallel to thefirst direction while surrounding an outer circumferential surface ofthe tube (Comparative Example 2), the degree of supersaturation in thearea may be different depending on the distance distant from theevaporation and condensation unit. For example, the relative humidity isabout 100% at a vapor generating position where vapor is generatedadjacent to the evaporation and condensing unit, and the relativehumidity increases as it approached to the central area of the tubealong the second direction. In addition, the relative humidity may bepartially reduced as an air-stagnant time is drastically reduced in acentral area of the tube. Therefore, the degree of supersaturationvaries depending on the position of the tube in the second direction.

When the evaporation and condensation unit 120 according to anembodiment of the present invention is inclined in the tube 110 at anangle of 5 to 90 degrees with respect to the first direction, theevaporation and condensation unit 120 may supply the steam into the areaat all of positions at which the evaporation and condensation unit 120is installed. The degree of supersaturation can be uniformed entirelyalong an arrangement direction in which the evaporation and condensationunit 120 is arranged.

Referring to FIG. 3, when the evaporation and condensation unit 120 isinclined at 90 degrees along the first direction, the area in the tubehas a uniform degree of supersaturation along the second directionperpendicular to the first direction in the tube 110. Thus, the vaporcan be condensed on the surfaces of the particles contained in the air,and the droplet can be uniformly formed as a whole.

For example, when the air supplied to the inlet has a relative humidityof about 80%, the relative humidity can be increased as a position isaway from the inlet along the X-direction and the area changes to asupersaturated state as the air passes through the area where theevaporation and condensation unit 120 is provided. It can be confirmedthat a uniform degree of supersaturation can be obtained along thesecond direction.

In an example embodiment of the present invention, the evaporation andcondensation unit 120 may be arranged entirely in the second direction,a vertically cross-section of the area perpendicular to the firstdirection. Thus, the evaporation and condensation unit 120 is entirelyin contact with the air which is flowing in the first direction.Therefore, the vapor supplied from the evaporation and condensation unit120 can be effectively condensed on the surfaces of the particlescontained in the air.

FIG. 4 is a graph showing a temperature distribution along a seconddirection (Y-direction).

Referring to FIG. 4, a temperature of the air flowing into the inlet hasan initial temperature T_(in), and the inner wall of the tube has a walltemperature T_(wall). As the air passes through the evaporation andcondensation unit 120, the temperature increases. In this case, the airmay have a uniform temperature distribution along the second direction(y direction). Therefore, the vapor can be uniformly condensed at thesurfaces of the particles included in the air along the seconddirection.

FIG. 5 is a cross-sectional view illustrating a wire included in anevaporation and condensation unit.

Referring to FIG. 5, the evaporation and condensation unit 120 mayinclude at least one mesh structure 120 which includes a plurality ofwires 121 randomly arranged. Reference numeral 120 denotes both anevaporation and condensation unit and a mesh structure.

That is, vapor may be supplied from each of the wires 121 to convert thearea into a supersaturated state. In addition, since each of the wires121 includes a heating element, the liquid retained in the wires can beeffectively vaporized.

A through hole may be formed between the wires 121. Crossing points maybe formed at specific points of intersection of the wires.Alternatively, the wires may be arranged on mutually different planessuch that they do not cross. At this time, the through hole may beformed between the wires.

On the other hand, a flow path through which the air can flow can beprovided through the through hole. As a result, the flow of air flowingin the first direction can be made uniform as a whole.

In an embodiment of the present invention, each of the wires 121 mayinclude a heating body 121 a for heating the liquid adjacent thereto. Inaddition, each of the wires 121 may further include a liquid-absorbinglayer 121 b. The liquid-absorbing layer 121 b may be made of ahydrophilic material that holds the liquid as a source of the vapor.Examples of the material constituting the liquid-absorbing layer 121 binclude cellulose, titanium oxide, and the like.

That is, since each of the wires 121 may perform both a heat generatingfunction and a steam supplying function, a wholly uniformsupersaturation degree can be maintained along the direction in whichthe evaporation and condensation unit 120 is arranged.

In other words, after the heating element 121 a generates heat, the heatis conducted toward the liquid-absorbing layer 121 b. The liquid held inthe liquid-absorption layer 121 b can be heated and vaporized.Accordingly, uniform supersaturation degree may be maintained as a wholealong the direction in which the evaporation and condensing unit 120including the wires 121 are arranged.

Thus, in the area having the supersaturated state, vapor is condensed onthe particles contained in the air flowing adjacent to the evaporationand condensation unit 120, such that a droplet containing the particlescan be formed.

In addition, a uniform temperature distribution may be realized alongthe second direction perpendicular to the first direction at a specificpoint along the first direction. That is, when the evaporation andcondensation unit 120 including the wires 121 is arranged along thesecond direction, a uniform temperature distribution may be achievedalong the second direction due to the heat generated from theevaporation and condensation unit 120.

Each of the wires 121 may includes a concavo-convex pattern on thesurface or a coating layer having a hydrophilic surface so as to receivea liquid using a capillary force. As a result, the wires 121 can holdthe liquid lifted by the capillary force from a liquid reservoir (notshown) located below.

In an example embodiment of the present invention, the liquid isvaporized by the heat supplied from the heating element 121 a at thesurfaces of the wires 121. Thus, a distance from a steam generationpoint where steam is generated from the wires 121 to the particlesincluded in the air and be adjacent to the wire 121 becomes relativelysmall. Therefore, the vapor generated from the wires 121 can more easilyreach to the particles contained in the air, such that the vapor can beeasily condensed on the surfaces of the particles.

FIG. 6 is a graph illustrating sizes of particles and droplets along afirst direction (X-direction).

Referring to FIG. 6, an additional evaporation and condensation unit 130(see FIG. 1) may be arranged in the tube 110 with being spaced from theevaporation and condensation unit 120. In this case, a plurality ofevaporation and condensation units 120 and 130 may be arranged to bespaced apart from each other. Accordingly, since the plurality ofevaporation and condensation units 120 and 130 are provided, a size ofthe droplet to be formed in the tube can be increased.

FIG. 7 is a flow chart illustrating a droplet generating method inaccordance with an example embodiment of the present invention.

Referring to FIGS. 1, 3, and 7, according to a droplet generating methodin 10 accordance with an example embodiment of the present invention,first air containing particles is supplied along a first direction in atube in which an area is defined (110). A vapor is then supplied to thearea to maintain a generally uniform supersaturation degree along asecond direction perpendicular to the first direction within the area,thereby condensing the vapor on the surfaces of the particles to producedroplets.

In order to maintain the uniform supersaturation degree, an evaporationand condensation unit which is arranged to intersect the first directionin the tube may be used.

In an example embodiment of the present invention, the uniformsupersaturation degree is maintained, and an entirely uniformtemperature distribution may be formed along the second directionperpendicular to the first direction at a specific point along the firstdirection.

The droplet generating device and the droplet generating methodaccording to example embodiments of the present invention canefficiently generate droplets by supplying vapor to the surfaces ofparticles having a relatively small size to condense the vapor on thesurfaces of the particles. Thus, the present invention may be applied toapparatus that can measure or remove pollutants.

The foregoing is illustrative of the present invention and is not to beconstrued as limiting thereof. Although a few exemplary embodiments ofthis invention have been described, those skilled in the art willreadily appreciate that many modifications are possible in the exemplaryembodiments without materially departing from the novel teachings andadvantages of the present invention.

What is claimed is:
 1. A droplet generating device comprising: a tubedefining an area in which air including particles flows along a firstdirection; and an evaporation and condensation unit disposed in the tubeto intersect with the first direction, the evaporation and condensationunit supplying vapor in the area to supersaturate the area to condensethe vapor on surfaces of the particles to form a droplet, wherein theevaporation and condensation unit has at least one mesh structureincluding a plurality of wires randomly arranged, and each of the wiresincludes a heating element being provided inside thereof and beingconfigured to heat liquid formed on surfaces thereof and aliquid-absorbing layer having an intrinsically hydrophilic material tobe capable of holding the liquid as a source of the vapor.
 2. Thedroplet generating device of claim 1, wherein the evaporation andcondensation unit is arranged to be inclined at 5 to 90 degrees withrespect to the first direction.
 3. The droplet generating device ofclaim 1, wherein the evaporation and condensation unit is arrangedentirely over a vertical section of the area perpendicular to the firstdirection.
 4. The droplet generating device of claim 1, wherein the meshstructure includes a through hole formed between the wires.
 5. Thedroplet generating device of claim 1, wherein the heating elementprovides heat for the liquid to vaporize the liquid.
 6. The dropletgenerating device of claim 1, wherein each of the wires includes aconcave-convex pattern for holding liquid using a capillary force. 7.The droplet generating device of claim 1, wherein each of the wiresincludes a hydrophilic surface coating layer for holding liquid using acapillary force.
 8. The droplet generating device of claim 1, wherein aplurality of mesh structures are spaced apart from each other along thefirst direction.
 9. The droplet generating device of claim 1, wherein asupersaturation degree is uniformly formed as a whole along a seconddirection perpendicular to the first direction at a specific point alongthe first direction.
 10. The droplet generating device of claim 1,wherein a temperature distribution is uniformly formed as a whole alonga second direction perpendicular to the first direction at a specificpoint along the first direction.
 11. A droplet generating method carriedout in the droplet generating device of claim 1 comprising: providingair including particles in the tube defining the area along the firstdirection; and providing vapor in the area and maintaining a uniformsupersaturation degree as a whole along a second direction perpendicularto the first direction to condense the vapor on surfaces of theparticles.
 12. The method of claim 11, wherein maintaining the uniformsupersaturation degree is performed using the evaporation andcondensation unit arranged in the tube to intersect with the firstdirection.
 13. The method of claim 11, wherein maintaining the uniformsupersaturation degree includes forming a temperature distributionuniformly as a whole along the second direction perpendicular to thefirst direction at a specific point along the first direction.